Attachment for boat propellers



1963 L. A. HEINTZELMAN 3,077,229

ATTACHMENT FOR BOAT PROPELLERS Original Filed March 10. 1960 Fig.

2 Sheets-Sheet 1 Fig. 2

Leo A. Heinfze/man INVENTOR.

All 01 22. BY m,

Feb. 12, 1963 A. HEINTZELMAN 3,

ATTACHMENT F OR BOAT PROPELLERS Original Filed March 10, 1960 2 e s-Sheet 2 Leo A. Heinrze/man INVENTOR.

BY 24mm WW 5M United States Patent Ofiice 3,977,229 Patented Feb. 12, 1963 3,077,229 ATTACHMENT FOR BOAT PROPELLERS Leo A. Heintzelmau, 499i) Burlingame, SW., Grandville, Mich. Continuation of application filer. No. 14,114, Mar. 10, 1960. This application July 17, 1%1, Ser. No. 124,686 7 Qlaims. (Cl. 170-16011) This application is a continuation of my co-pending United States patent application Serial No. 14,114, filed March 10, 1960 and entitled Attachment for Boat Propellers, now abandoned.

The present invention generally relates to an attachment for a boat propeller and generally is an improvement on that type of construction disclosed in my prior Patent No. 2,885,012 granted May 5, 1959.

Engines which are employed in boats produce maximum horsepower at a relatively high rotational speed. In view of the resistance of the Water to rotation of a propeller driven by a boat engine, it requires an extended period of time for the boat engine to reach its optimum operating speed. It is the primary object of the present invention to provide an attachment for a propeller for a boat, the attachment generally including a pair of movable blades mounted on the propeller which are extended under the influence of centrifugal force as the propeller reaches a predetermined rotational speed thereby maintaining the initial resistance to rotation of the propeller at a minimum so that the engine may reach optimum operating speed more easily with the extensible blade being automatically operated by centrifugal force to increase the propulsion qualities of the propeller after the engine has reached optimum operating speed.

A further object of the present invention is to provide an attachment for a propeller in the form of an extension for each blade of the propeller that is normally retracted to a position alongside of the blades of the propeller but which is automatically extended by centrifugal force when the propeller reaches a predetermined rotational speed.

Still another object of the present invention is to provide an attachment for propellers in accordance with the preceding objects in which the extensible blades are spring biased to a retracted position with the tension on the spring being adjustable for varying the speed at which the extensible blades are actuated.

A still further object of the present invention is to provide an attachment for propeller blades of the character described in which the extensible blades are provided with guides for retaining the extensible blades rigidly in relation to the propeller blades during the movement between the extended and retracted position.

Yet another important feature of the present invention is to provide an attachment for a boat propeller which is simple in construction, easy to attach, efficient in operation and generally inexpensive to manufacture.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is an end elevational view of a boat propeller with the attachment of the present invention installed thereon;

FIG. 2 is a side elevational view of the construction of FIG. 1;

FIG. 3 is a view similar to FIG. 1 but with the extensible blades in partially extended position;

FIG. 4 is a detailed view of the mounting means for the extensible blades with the cover removed;

FIG. 5 is a detailed sectional view taken substantially upon a plane passing along section line 5-5 of FIG. 4 illustrating further structural details of the mounting means for the extensible blades;

FIG. 6 is a detailed sectional view illustrating the guide mechanism on the extensible blades;

FIG. 7 is an exploded group perspective. view of the mounting assembly for the extensible blades; and

FIG. 8 is a sectional view similar to FIG. 6 but illustrating the attachment without the guide flange for enabling the attachment to be used as a weed cutter,

Referring now specifically to the drawings, the numeral 16 generally designates a propeller on which the attachment of the present invention is mounted with the attachment generally being designated by the numeral 12. The propeller 10 includes a central hub 14 therethrough for receiving the tapered end of a propeller shaft. Suitable means may be provided in the hub 14 for locking the propeller 10 onto the propeller shaft or onto the drive shaft.

Radiating outwardly from the hub 14 is a pair of blades 16 which are of identical construction and which are set at a desired angle depending upon the particular type of motor or engine with which the propeller is to be associated. The propeller structure as far as the hub and the orientation of the blades 16 is concerned is conventional. Each blade 16 is provided with a leading edge 18 and a trailing edge 21) and also an outer curved edge 22.

The attachment 12 is the same for each of the blades 16 and only one attachment will be described and this includes an extensible plate 24 generally conforming in curvature to the outer edge 22 and a portion of the leading edge 18 of the blade 20. The extensible plate 24 is provided with a curved outer edge 26 and a concave inner edge 28 lying alongside one surface of the blade 16. The edges 26 and 28 generally converge towards the trailing end and terminate in a point 30. The curved edge 26 is actually a reverse bend with. there being a flange 32 integral therewith which extends alongside and engages the opposite surface of the blade 16 in relation to the extensible plate 24- thereby forming a guide for movement of the extensible plate 24 between a retracted position as illustrated in FIG. 1 and anextended position as illustrated in FIG. 3. The guide flange 32 serves to stabilize the extensible blade 24 and retain it in alignment with the propeller blades 16. In certain installations, the guide flange 32 may be omitted with the curved edge 26 still extending across the outer edge 22 of the blade 16 for limiting the inward movement of the extension blade 24.

The propeller blade 16 is provided with an opening or aperture 34 therein which has a square counterbore or recess 36 communicating therewith which receives a square shoulder 38 on a fastening pin 40 which is also provided with an enlarged rather flat rounded head 42. The round fastener 40 extends through the aperture 34 and the square shoulder 38 is received within the recess 36 thereby preventing rotation of the fastener 40.

The fastener 40 is provided with a longitudinally extending slot 44 therein and the outer end of the legs formed by the slot '44 are provided with aligned apertures 46.

The propeller blade 24 is provided with an enlarged aperture 48 having a pair of outwardly extending notches 50 in the Wall thereof with the notches 5t) being circumferentially spaced. Disposed in the opening 48 is a spiral flat spring 52 having the outer end thereof offset or extending radially outwardly as indicated by the numeral 54 for reception in one of the notches 50. The inner end is offset inwardly or extends inwardly as designated by the numeral 66 for positioning in the slot 44 of the fastener 40. Thus, the spring 50 is disposed in the aperture 48 3 and the shoulder 38 is received in the recess 36 in the propeller blade 16.

The fastener 40 also extends into a socket or hollow interior 58 of a closure cap 60 having a depending or inwardly extending or peripheral edge 62. Extending through apertures 64 in the cap 60 is a cotter key 66 which also extends through the apertures 46 in the fastener 40 thereby anchoring the assembly together and permitting detachment thereof for replacement of parts or adjustment of the spring by placing the tine or finger 54 in selected notches 50.

When the extensible blades 24 are in normal position, the spring will retain the extensible blade alongside the surface of the propeller blade 16. However, when the speed of rotation of the propeller increases so that the centrifugal force overcomes the tension of the spring 52, the extensible blades 24 will pivot outwardly about an axis formed by the fastener 40 either with or without the guide flange and the increased size of the propeller caused by the extensible plates or blades will increase the efliciency of the propeller and cause a boat or the like to be propelled through the water or the like. The present invention requires only very little modification of an existing boat propeller with the attachment being readily installed by substantially anyone.

In FIG. 8, there is illustrated a modified form of the invention in which the attachment 24 that is secured to the blade 16 is provided with a straight and generally tapered edge 26' rather than the reverse bend 26. This construction will enable the attachment 24' to be used to cut weeds when this function is needed which is especially desirable in areas having considerable Weed growth.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

I claim:

1. An attachment for a boat propeller comprising an extension blade for each blade of the propeller, each of said extension blades having a curved outer edge adapted to generally conform to the outer edge of a propeller blade, means at one end of each extension blade adapted to pivotally mount it on a propeller blade, resilient means interconnecting said pivotal mounting means and a portion of said extension blade adjacent said pivotal mounting means, said resilient means being adapted to engage said extension blade and said pivotal mounting means to resiliently urge the extension blade to a retracted position alongside of the propeller blade.

2. The structure as defined in claim 1 wherein each extension blade is provided with an inwardly extending guide flange adapted to engage the opposite side of the propeller blade from the extension blade thereby guiding the extension blade during pivotal movement thereof.

3. In combination with a propeller having a plurality of propeller blades, an extension plate for each of said propeller blades, said extension plate having an outer edge conforming to the outer edge of the propeller blade, a fastener extending through and rigidly attached to the propeller blade, said fastener pivotally supporting one end of said extension plate, a pivotally resilient spring extending between said fastener and said extension plate, said spring having one end held'by the fastener and the other end held by the extension plate for biasing the extension plate to a retracted position.

4. The combination of claim 3 wherein said fastener is provided with a removable cap detachably secured thereto, said cap having a hollow interior surface for enclosingand concealing said pivotally resilient spring.

5. The combination of claim 3 wherein said extension plate is provided with a reversely curved flange on the outer edge thereof forming a guide for straddling the propeller blade thereby guiding the extension plate during pivotal movement thereof.

6. The combination of claim 5 wherein said pivotally resilient spring is a spiral spring and said spiral spring includes an outwardly extending finger on the outer end thereof, said extension plate having an enlarged opening receiving the spiral spring with the periphery of the opening having a plurality of circumferentially spaced notches for receiving the finger thereby adjusting the tension on the spiral spring.

7. The'structure as defined in claim 1 wherein each extension blade is provided with a tapered straight outer edge adapted to cut weeds growing in the water.

References Cited in the file of this patent UNITED STATES PATENTS 1,373,331 Hupp Mar. 29, 1921 2,885,012 Heintzelman May 5, 1959 2,992,686 Heintzelman et al. July 18, 1961 

1. AN ATTACHMENT FOR A BOAT PROPELLER COMPRISING AN EXTENSION BLADE FOR EACH BLADE OF THE PROPELLER, EACH OF SAID EXTENSION BLADES HAVING A CURVED OUTER EDGE ADAPTED TO GENERALLY CONFORM TO THE OUTER EDGE OF A PROPELLER BLADE, MEANS AT ONE END OF EACH EXTENSION BLADE ADAPTED TO PIVOTALLY MOUNT IT ON A PROPELLER BLADE, RESILIENT MEANS INTERCONNECTING SAID PIVOTAL MOUNTING MEANS AND A PORTION OF SAID EXTENSION BLADE ADJACENT SAID PIVOTAL MOUNTING MEANS, SAID RESILIENT MEANS BEING ADAPTED TO ENGAGE SAID EXTENSION BLADE AND SAID PIVOTAL MOUNTING MEANS TO RESILIENTLY URGE THE EXTENSION BLADE TO A RETRACTED POSITION ALONGSIDE OF THE PROPELLER BLADE. 